240Z Rear Disk Brake Conversion

Contributed By: Pete Sprenger; IZCC #5080

As Of: 12 Dec. 2002
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Rear Disk Brake Conversion Using 240SX Parts and Modern Motorsports Brackets

The really great thing about this conversion is that I should still be able to use my 14" street tire wheels with 70 series tires (it is nice to have tall sidewalls when you have stiff coil-overs).

This conversion is so easy I can't believe it. Anyone who wants 11.4" rear disk brakes can have them. It is a true bolt on conversion. Here are some pics of my process.

ABOVE: First I removed my wheels, pulled off the drum and removed the brake shoes and all the springs.

Next I freed the brake lines from their supports on the body. I quickly unscrewed one connection at a time, pulled the ends out of the hole, then fastened them back together again. I used a pry bar to push down on the brake pedal and hold it part way down. That way when I disconnected my brake lines I didn't loose more than a drop or two of fluid. This made bleeding the lines much easier later.

ABOVE:Next I needed to get the wheel cylinder out of the way. I removed the brake line from the back, disconnected the parking brake, pried off the rubber boot and removed the two clips that held it in. Then it just pulled right out. I wasn't ready to hook up the new calipers yet, so I just hooked the wheel cylinder back up to the brake line and hung it out of the way.

ABOVE:Now the real fun began! I love it when I get to use power tools to cut up my car! :)

ABOVE:The Sawzall really went through the backing plate quickly. I had to be careful not to cut into the hub. I stopped frequently to see how close I was getting. I cut both sides as close to the hub as I could.

ABOVE:Next I undid the 4 bolts that hold the backing plate up against the hub. A box end wrench works nicely for this. I pulled the plate away from the hub and used a Dremel with a cutting tool to cut as much as I could on both sides.

ABOVE:I couldn't get the Dremel to cut it all the way through without going into the hub, so I just wiggled it back and forth 4 or 5 times and it came apart on its own.

ABOVE:I painted the hub up nice and pretty so the project would look nice when it is done.

ABOVE:The bracket from Modern Motorsports bolted right into the existing holes that the backing plate bolted to. The fasteners were even included in the purchase price so I didn't have to go searching for metric bolts.

ABOVE:This is basically what it looks like when it is done. I still hadn't hooked up the braided stainless steel brake lines that I got from Modern Motorsports when I took this picture, but that is pretty much what it looks like. Although, my calipers are really red not orange. I don't know why the camera did that.

Emergency brake hook up

ABOVE:In order to make room for the emergency brake cable I first routed the stainless steel brake cable using the brackets from the hard line that I removed. I had to cut the rubber isolator down for the new line to fit.

ABOVE:The 240SX caliper has a tail like bracket that the ebrake cable hooks up to. I cut the old hard line bracket off of the frame to give a little more room for the 240SX bracket since I didn't needed the old one anymore.

ABOVE:This is the ebrake adaptor that Modern Motorsports sells. I suppose I could have made this part myself, but this one is nice because it comes already drilled to the right dimensions and includes all the connecting hardware. It is also nicely plated to match the rest of the parts.

When I went to hook up the ebrake cables to the caliper, the cable was way too long. It stuck out of the wheel well. A quick email to Modern Motorsports (their customer service is great) and I found out that if you switch the cable sides the lengths come out to be just about perfect. So, I moved the left cable over to the right and the right over to the left, switched the little springs that hold the cables up by hooking them to the floor of the car and everything lined up.

ABOVE:This is what the ebrake cable looks like when it is all hooked up. You can see how the adapter plate works.

Oh, and no car project is complete without a beautiful female. :)

I am upgrading to the 86 - 88 Toyota 4 piston calipers and 84 - 85 300ZX non-turbo vented rotor for the front brakes. This requires a machined spacer to center the rotor in the caliper. I also have a set of KVR carbon fiber pads for the calipers. So check back here later to see pics of the front brake project.